Drill device



Dec. 25, 1951 ATKlNSON 2,579,720

DRILL DEVICE Filed NOV. 12, 1948 1' |5 INVENTOR "f THOMAS P. mmsou it;:5. J BY m ATTORNEYS Patented Dec. 25, I951 UNITED STATES PATENT OFFICEDRILL DEVICE Thomas P. Atkinson, Newport Beach, Calif. ApplicationNovember 12,'194s,'seria1 No. 59,523

4 Claims.

This invention has to do with drills and, while not limited to such use,is particularly suited for use as an impact drill in mining operationsand the like where no liquid is circulated around the drill and throughthe hole to remove cuttings.

Usually such drills are operated by conventional jack hammers whichimpart the percussive blow to the drill stem, the drill bit carried bythe stem being usually shaped to impart rotative movement in response tothe impact. In such drilling there is a tendency, particularly incertain earth formations, for the drill to become wedged against removalfrom the hole due to cuttings tending to wedge behind the drill when thedrill is pulled axially outwardly of the hole.

It is an object of my invention to provide a drill device which iseasily removable from drill holes bored in any earth formation.

A further and more particular object is to provide a drill stem whichhas means for loosening the drill in the hole to permit its readyremoval.

Other subordinate objects and accomplishments of my invention willbecome apparent from the following detailed description of a presentlypreferred embodiment, for which purpose I shall refer to theaccompanying drawing, wherein:

Fig. 1 is a side elevation;

Fig. 2 and Fig. 3 are sections taken on lines 2-2 and 3-3, respectively,of Fig. 1;

Fig. 4 is an enlarged fragmentary side elevation;

Fig. 5 is an enlarged cross section of one of the vanes on the drillstem; and

Fig. 6 is a side elevation of the device in a drill hole.

Referring now to the drawings. I show at 5 a drill stem having a flange6 at its upper end and a reduced diameter upper end 1 of angular crosssection to fit in a socket in an additional length of drill stem or inan impact member (not shown).

The stem is preferably, though not necessarily, of hexagonal crosssection, and has a relatively large diameter, substantially cylindricallower end portion 8 and a portion 9 tapering from the portion 8'to therelatively small diameter upper stem portion.

Depending axially from the lower end of the stem there is a screwthreaded tapered pin I0 for attachment to a drill bit l5. While myinvention is not confined to the use of any particular bit or drillelement, the bit illustrated is a conventional star bit having acylindrical body portion 20 with formation impacting end members orcutters 2| whose formation engaging faces are angled to cause rotationof the bit in the direction of the arrow 22 as the bit is driven intothe formation.

' The cylindrical lower end portion 8 of the stem is preferably the samediameter as the body of the bit, so as to prevent any earth fromimpacting beneath the bottom end of the stem above the bit.

The cylindrical portion 8 oi the stem is provided with spirally disposedgrooves 25, here shown as three in number, spaced apartcircumferentially of the stem, although, of course, any desired numberof grooves may be employed. These grooves extend into the taperedportion 9, although they gradually decrease in depth toward the top endof the tapered portion-that is, as the grooves traverse the taperedportion, they gradually reduce in depth due to the tapered or conicalshape of the portion 9.

In each of the grooves I secure, as by brazing or welding, a vane 30.Considering that the tool, when in operation, is caused by the shape ofthe bit to rotate in the direction of the arrow 22, in such normaloperation the left-hand edge of each vane would be the leading edge Weand the opposite edge would be the trailing edge b. Preferably,throughout the cylindrical section 8, the leading edge 30a of each vaneis substantially flush with the peripheral surface of the portion 8, andthis is preferably true also as the vanes traverse the tapered portion9, since, in normal operation, it is not desired that the vanes performany reaming action. However, the faces of the trailing edges 3% projectradially from the periphery of the stem to an extent not greater thanthe diameter of the hole H cut by the bit, the outer surface 30c of eachvane declining from its normal trailing edge to its normal leading edge.As will be best seen in Fig. 4, the trailing edge projects radially fromthe peripheral surface of the stem to a gradually increasing extent fromthe cylindrical portion 8 towards the upper end of the tapered portion9.

The vanes are spiralled in a direction opposite to the direction ofnormal rotation of the stem during drilling operations, so that when thestem is pulled axially upwardly from the hole the faces 30?) of thevanes engage any loose earth in the hole above the bit and imparting areverse rotative movement to the stem-that is, in the direction of thearrow 35-preventing the tool from wedging in the hole. Since the edge orface 39b of each vane gradually decreases in thickness towards the lowerend of the stem portion 8, which is slightly smaller in diameter thanthe hole, the

' the lower end of "said stem and shaped to impart rotation to the drillstem in a given direction in response to percussive engagement of thebit with the bottom of a hole being bored, spirally longitudinallydisposed circumferentially spaced vanes projecting from the peripheralsurface of the stem, the outer surfaces of the lower end portions ofsaid vanes and maximum diameter portions of the bit defining thediameter of the hole being bored; each of said vanes spirally retreatingfrom its lower end to its upper end when viewed in relation to thedirection of rotation of the stein and bit during normal boringoperation, and each having a sloping normally leading surface and aradial normally trailing surface. H

2. In a drill device, the combination with a percussive drill bit havinga formation engaging surface arranged to impart rotative movement to thebit in a clockwise direction in response to percussive e ga em nt of thebit against said formation, of a drill stern having acylindrica-lportion connected to said bit, and having perip'h 7 arm vanes spirallydeclining from the 1ower and to the ripper end of -said drill sterncounterclockwise direction, said vanes resentmg sloping formationengaging surfaces facing toward said direction of rotation and radialsurfaces facing in the opposite direction, whereby upon rotation of thebit and stem in the latter direction to move looseformation downwardlyfrom above the bit.

3. In a drill device, the combination with a percussive drill bit havinga formation engaging surface arranged to impart rotative movement to thebit in a clockwise direction in response to percussive engagement of thebit against said formation, of a drill stem having a cylindrical 1portion connected to said bit, having a portion above said cylindricalportion tapering to a smaller diameter upper end portion and havingperipheral vanes spirally declining from the lower end to the upper endof said drill stem in a counterlockwise direction, said vanes presentingsloping formation engaging surfaces facing toward said direction ofrotation and radial surfaces facing in the opposite direction, wherebyupon rotation of the bit and stem in the latter direction to move looseformation downwardly from above the bit.

4. In a drill device a drill stem formed at its bottom end to receive apercussive drill bit shaped to irnpartrotation thereto in a clockwisedirection in response to percussive action, said stem having acylindrical lower end ortion and tapering upwardly to a relatively smalldiameter cylindrical upper portion, and having peripheral groovestraversing said cylindrical and tapered portions, said grooves spirallydec'ning 1m their lower ends to their upperenas 111a count clockwisedirection, and varies having their'in edges secure" said respectivegrooves, said vanes presenting sloping surfaces racing said direction ofrotation and presenting radial surfaces facing the opposite direction.

THQMAS P. ATKINSON.

REFERENCES CITED The "re-mowing references are -61 record mine a file ofthis patent:

UNITED sures ierces

